I own both a 7D and a 350D, and don't plan on moving to FF at this stage. The balance between size, cost, functionality and having the pixel density on my telezoom end makes me enjoy using crop sensored cameras a lot.
Having said that, sure there are some times that I would like a FF - particularly for more depth of field control.... but even that will be minimised when I hope to Canon will produce, and then I'll buy a great new Canon 50-60mm prime (eg f1.8 to f2 with true USM and superior IQ wide open).
I see that I might possibly never go to FF (so long as there are always APS-C sensored bodies and EF-S lenses around) - ie to replace my current bodies / lenses when they might 'die'.
From a size perspective, the 7D is ideal for me. I upgraded from the Canon 350D (which I've had since 2005) to the Canon 7D about 2 and a half years ago. I haven't looked back since. The 7D's superior handling, AF and image quality were welcome to me. I got used to the 7D's sound very quickly. In particular the 7D's view finder and screen have been great practical benefits, as well as the higher ISO possibilities.
The 7D is just the camera I want / need. Sure, I hope any 7DmkII will have improved IQ and perhaps a few additional features. I'm very happy with the 7D's AF and fps - though any improvement on either of these would be ok (so long as the price rise isn't too substantial just because of that). Whenever I go back to the 350D, it takes me a bit of getting used to (eg a few minutes of using) - but then I am ok with it. But the 7D feels more natural to me now.
My lenses include a Sigma 10-20mm EX, Canon 15-85mm, Canon 100mm macro and Canon 70-300mmL. The image quality from all of these lenses is very very good - from 10mm to 300mm (in 35mm equivalent: 16mm to 480mm) is well covered. So I find these all work so well on crop sensored cameras, particularly corner to corner of the frame.
From a camera size perspective, I have used a 1D series, and find it uncomfortably heavy / big. I'm a fit - yet fairly small build guy, but having that additional weight of a 1D does take it's toll. I can use my 7D with 70-300mmL for hours walking, etc, but a bigger camera and lens combination (eg 1D with 100-400mmL) is much more tiring.
I have small to medium size hands, but my fingers are relatively long for the size / shape of my hand. Many people talk about 'small hands' or 'large hands' - but I think it's to do with many aspects, eg length of palm, length of fingers, 'stubby vs thick' fingers, etc. The 7D has both a taller and a 'beefier' grip for all my fingers to curl around. Having said that, I managed to use a 350D for hours - there was some discomfort, but I often just ignored it. I have used a Sony Nex 7 the other day - (helping a friend of mine who needed my assistance) - and I found the whole size and system too 'fiddly'. I would rather have a good P&S for ultimate portability in that case (as I used to have a few Fuji P&S cameras before I got into DSLRs).
From a perspective of image quality, pixel peeping will at times allow people to tell whether a photo was taken with the latest / greatest FF from an entry level APS-C... however, good photographers can get awesome images from even entry level DSLRs, as they understand about light, composition, technique and post processing. I have seen many many good photos across all levels of cameras, including P&S, though it's true that cameras with larger sensors have discernable benefits - particularly in noise, sharpness-per pixel level and functionality (eg fast focus, low-light, etc).
Some of the photos I took several years ago with my Fuji 3MP P&S still 'wow' people (who are not pixel peepers), as well as many images from my 350D. As I had those cameras for my years (about a decade) living in Europe between the late 90's to late 2008 - I'm glad to have those digital images captured and saved (forever!) However I'm now most content with the 7D, and if I ever go travelling, that is what I take as my main kit - with the 350D as my backup.
Regards... hope my post is useful food for thought!